Limit to number of tasks?

Why does Gantter stop allowing me to enter additional tasks? It started when I hit 50 tasks.I've had to close and then reopen my project to enter additional tasks. But the program stops again after I've enter about 5 additional tasks.

Hi all.
"Insert below" worked for me as well. I had a little where it wouldn't indent the tasks when below row 49. An error popped up. I have reloaded the whole page and the glitch disappeared. It also added 5 new rows below the last one.